The present invention relates generally to communication, and more specifically to a hands-free voice communication apparatus.
Hands-free voice communication devices are commonly used for many applications such as speakerphone, hands-free car kit, teleconferencing system, cellular phone, hands-free voice recognition device, and so on, and in various environments such as car, home, office, hotel, and so on. A hands-free device allows a near-end user to speak into one or more microphones placed at some distance away from the near-end user and to listen to sound from a far-end user via a loudspeaker also placed away from the near-end user. Hands-free devices are thus convenient and comfortable to use, and are also safer to use than hands-on or handheld devices in certain situations, e.g., when driving a car.
A hands-free device typically supports hands-free voice communication via a speakerphone that includes a loudspeaker and one or more microphones. When the hands-free device is small in size, the close proximity of the loudspeaker to the microphones can cause some major problems. For example, when a speech signal from the far-end user is outputted from the loudspeaker, a portion of this speech signal may be reflected back to the microphones and transmitted back to the far-end user. This acoustic disturbance is referred to as echo. In general, users are annoyed by hearing their own voice delayed, for example, by the path of the system. In certain instances, acoustic shock or howling may be caused by the speakerphone becoming unstable due to the microphones picking up reflections of the acoustic signal emitted by the loudspeaker.
Hands-free devices are described in various literatures including U.S. Patent Application Serial Nos. US 2003/0157973 and US 2004/0033820. Application Serial No. US 2003/0157973 describes installing an earpiece inside a cellular phone and using a switch to select between the cellular phone and the earpiece. US 2003/0157973 does not describe a speakerphone feature for the cellular phone. Application Serial No. US 2004/0033820 describes a handset that communicates via infrared with a hands-free kit having an earpiece. However, US 2004/0033820 does not address integration of a speakerphone.
As can be seen, a hands-free voice communication device that can effectively provide hands-free communication is highly desirable.